The subject invention relates to an automotive seat assembly having a seat track mechanism with a fixed positioning device for positioning the seat assembly as the seat is returned from a forward dumped position.
Automobiles and other vehicles are equipped with various seat assemblies that arm each adjustable to many intermediate locations between forward and rearward positions. Sliding a seat forward or rearward to a particular location is desirable for enhancing an occupant""s comfort. In most two-door vehicles the front seats arc also capable of automatically moving to a single forward dumped position by simply actuating a lever and pushing a seat back forward This forward movement of the seat assembly permits easier access into a sear seating or rear cargo area.
These forward and rearward movements of the seat may be accomplished by a dual seat track mechanism or a single seat track mechanism. The single seat track mechanisms typically include an upper seat track member movably supported on a lower seat track member. The upper seat track member is mounted to the seat cushion of the seat assembly and the lower seat trace member is mounted to the floor of the vehicle. There is also typically a locking mechanism for securing the upper seat track member to the lower seat track member.
There is also typically a slide actuator for releasing the locking mechanism and propelling the upper seat track member to the forward dumped position The slide actuator is activated by actuating the lever and pushing a seat back of the seat assembly forward. A pretensioned spring urges the seat forward to the forward dumped position, thereby allowing easier access into the rear seating or storage area. The seat bottom, seat back, and all other seating accessories move forward together to the forward dumped position. When access to the rear seating or storage area is no longer desired, the user simply pushes the seat back rearward which re-engages the locking mechanism with the lower seat track member.
As the seat by is being returned to its original seating position, it is desirable to have some type of positioning feature that allows the seat assembly to return to a position which allows access for the front passenger without the seat moving to the rearward most position.
One such positioning feature is disclosed in British Patent No. 2 255 903. The ""903 patent includeand a walk in mechanism mounted to an upper track and interconnected to a seat back of the seat assembly. The walk in mechanism includes a lever and a trigger for releasing the seat tracks when the seat assembly moves to a forward dumped position and for automatically re-securing the seat tacks at a predetermined position when the seat assembly is returned from the forward dumped position. The ""903 patent requires that the , seat back be folded over a seat cushion in order to release the seat tracks and that the seat back be returned to an operative position, i.e., upright, when returning the seat assembly from the forward dumped position. During the returning movement of the seat assembly, the trigger interferes with a fixed stop which moves the lever such that the lever can allow the seat tracks to re-secure the seat assembly at the predetermined location. If the seat back is not in the operative position during this return movement, the lever prevents the seat tracks from resecuring the seat assembly. Hence, if the seat assembly is returned from the forward dumped position with the seat back overlaying the seat cushion, as is commonly done, the seat track locking mechanism is capable of locking the seal assembly in an undesirable position aft of the fixed stop. This obviously defeats the entire purpose of the mechanism as disclosed in the ""903 patent. Accordingly, it would be desirable to develop a mechanism that cannot be easily defeated or overridden. The prior art has also contemplated a xe2x80x9cmemoryxe2x80x9d feature such that the original incremental adjustment position is retained. The prior art memory devices are typically separate slides which independently mount to the seat track mechanisms. The sliders are then periodically moved by the locking mechanism to maintain the desired memory position. Examples of these prior art memory devices are disclosed in U.S. Pat. Nos. 4,881,774 , 4,952,846, and 5,100,092, and British Patent No. 2 303 299. These prior art devices, however, are of a relatively complicated design with a number of moving pars which add to the cost, weight and complexity of the seat assembly. In addition, these prior art devices can malfunction which reduces the effectiveness of the memory feature. Finally, the prior art memory devices limit the overall range of forward and rearward movement of the seat assembly.
The disadvantages of the prior art may be overcome by providing a seat assembly having a seat track mechanism which incorporates a seat dumping feature and a positioning feature of a relatively simple construction to reduce the cost and weight of the design. The positioning feature should locate the seat in a predetermined position when the seat is returned from the forward dumped position. In addition, the positioning device should be designed so as to not be prone to failure and not limit the overall adjustment capability of the seat track mechanism.
According to one aspect of the invention, there is provided an automotive seat assembly having a seat cushion and a seat back mounted to the seat cushion. The seat assembly includes a seat track mechanism having a lower track member and an upper track member mounted to the seat cushion and movably supported by the lower track member for movement between forward and rearward positions. An incremental locking mechanism is mounted between the upper and lower track members for selectively locking the track members in a desired position and for selectively unlocking the track members to allow the upper track member to move between the forward rearward positions. A slide actuator is disposed adjacent the locking mechanism and is selectively moveable to an enraged position for disengaging the locking mechanism and slidably moving tho upper track member to a forward dump position. The assembly is characterized by a locator mounted to the upper track member and moveable with the upper track member as the upper track member is moved to the forward dump position. The locator is interconnected to the slide actuator wherein the locator moves between a release position allowing the upper track member to freely move relative to the lower track member and a blocking position to limit movement of the upper track member to a predetermined stop position upon rearward movement of the upper track member from the forward dump position. Accordingly, the subject invention provides a positioned device of a relatively simple design and of minimal weight and cost to the seat assembly. The positioning device does not interfere and remains dormant during the normal forward and rearward incremental movement of the seat track mechanism. This creates a positioning device which does not limit the overall movement of the seat track mechanism. In addition, due to the low number of moving parts and ease of operation, the subject invention is not prone to failure.